{
	let arr = [ 1, 2, 3 ]

	let arr1 = arr.slice()
	console.log(arr1)

	// 可选参数
	// let mySlice: (a:string,b?:string)=>void = (a,b)=>{
	//     console.log(a,b)
	// }

	// mySlice('1')
	// mySlice('1', '2')

	// 默认值
	// let mySlice: (a:string='1',b:string="2")=>void = (a,b)=>{
	//     console.log(a,b)
	// }

	function mySlice(a: number, b: number = 2): void {
		console.log(a, b)
	}

	mySlice(1)
	mySlice(1, 2)
}
